Hello, first time poster at DIY,
My house currently has two 3-way switch controlling a light at the
downstairs entrance. I like to turn one of the 3-way switch located at
the lower floor to a motion sensor wall switch.
I opened up the existing 3-way switch box and it has 3 terminals with
3 wires (black, red, white), how do I hook it up to my motion sensor
switch which has 2 black wires and 1 green (ground wire)? My goal is
to make the top floor switch either an independent switch, or "3-way"
with the motion wall switch.
Any help is appreciated. Thanks.
Actually, if you look, you'll find your three-ways actually have 4 wires
- red, black, white and bare copper (the ground)
The problem you're going to have is that a three-way switch actually
works like this (bad ascii art coming up)
2 black 4
1 / o-----------------o \\ 6 black 7 8 white
black ----o/ \\o-----------o(L)o-----------.
3 red 5 |
Consider the "o"s to be the terminals on the switch body; the ground
line is left off since it's not electrically part of the circuit. Each
switch can move to either the 'red' connection (terminals 3 and 5) or
the 'black' (terminals 2 and 4). The idea is if both switches are on the
same line, the light will be on. Since they have to be on one or the
other, changing just one switch can turn the light on or off, at either end.
Now if you replace one of the switches with the motion sensor switch,
since it has only two connections (the black wires; again, the ground
doesn't count, for our purposes), you could connect to either the red
line or the black line, but not both.
2 black blk
1 / o---------x---[M]---. blk black 7 8 white
black ----o/ `-----x------o(L)o-----------.
3 red |
Let's say it was connected to the black line from terminal 2. A safety
problem then arises, as it would be possible for the switch to be set to
the black line, which would now be energized but unconnected in the
other switch's box. To avoid the safety hazard, you would have to also
disconnect and terminate the red wire at terminal 3 in the remain switch
box - then all you have is a piece of wire running through the walls.
One of the things you don't say is how you want this to work. Do you
want the light to go on and off with the motion sensor detection, but
have the switch override it, so you can turn it on and leave it on? Or
turn it off and leave it off? Or both?
"Take sides! Always take sides! You may sometimes be wrong - but the man
who refuses to take sides must *always* be wrong! Heaven save us from
Nice ASCII art.
I agree that the OP is unclear what the swtiching is intended to do.
As shown, in one switch position the light will come on only when there
is motion. In the other switch position the light will never come on.
Another possibility is one switch position the light comes on only when
there is motion. The other position the light is always on. To get that
- at the motion detector end connect the red to the black going to the
light - terminal 5 to 6.
You could also connect it so both 3-way switches work but a motion
detector will always turn on the light.
In the first diagram the white wire will probably connect to terminal 1
or 6. In any case, when you look at the existing 3-way switch, 2
terminals will be the same color and one will be different. The
different color will be terminals 1 and 6. Keep track of which wire it is.
What powers the motion detector?
Here it is:
Model number I have is SL-6105 (single pole)
Manual is: http://126.96.36.199/manuals/595-4881-09J.pdf
I like the idea of using the motion sensor as a over-ride, meaning it
will be triggered on by motion but only comes off when I turn off the
Can it be done? How?
I like to replace the lower floor light switch to a motion sensor so
it will trigger the light to "on" but turn off by either the manual
override on the motion sensor switch or the upper level switch (no
Thanks for any suggestion.
On Jul 15, 2:32 pm, email@example.com wrote:
It is possible that turn-on-with-motion, turn-off-manually is built into
some motion-detector-switch. What happens when your switch comes on with
motion and you turn it off. I presume you saw your switch stays on for
an adjustable time. Check the manual for the 3-way version of the switch
you have what happens when it turns on with motion and then the 3-way
circuit is turned on and off.
It could be done with a relay, but that is a lot of complication.
As John said, you might want to use a 3-way version of what you have.
Simple. Go to the nearest borg and buy a 3-way motion sensor switch.
Carefully follow the instructions that come with it -- you'll have to
mess with the switch wiring at both ends of the circuit but there is
nothing difficult involved. The ones that I've used were made by Eagle
which I believe was stocked by Lowe's but there are others and all are
essentially identical. BTW, I've found that the switches do not work
properly with a load which is solely CF but they do work fine with
incandescent -- some peculiarity of how operating current is provided to
the detector circuitry in the switch, I'm sure.
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